Adjustable magnet support for electric switches and relays



Aug- 18, 1936. D. M. HoLBRooK 2,051,298

ADJUSTABLE MAGNET SUPPORT FOR ELECTRIC SWITCHES AND RELAYS Filed June 27, 1954 Q F35, e

/NS l/L 6770/1/ Patented Aug. 18, 1936 UNITED STATES PATENT OFFICE ADJUSTABLE MAGNET SUPPORT FOR 3 Claims.

My invention is directed toward improvements in automatic switches of the type provided with magnets which hasten their opening and closing. My invention particularly relates to a switch of the foregoing type which is provided with an adjustable support for a magnet whereby such magnet can from time to time be adjusted in Order to compensate for the wearing away of the contact points of the switch, thus ensuring the proper operation of such switch at all times.

The primary object of my invention is to provide a switch structure of simple construction and positive operation embodying a magnet which hastens both the opening and closing thereof, and

l which magnet is so constructed or supported that the position of its poles may be altered with reference to the contact points of such switch thereby at all times utilizing to the fullest extent its magnetic lines of force regardless of structural changes in such contacts.

Another object of my invention is to provide a magnetic controlled switch, either automatically or otherwise operated, which is provided with an exceedingly simple mechanism for moving the poles of the Vmagnet relative to the contact points of such switch.

Another object of the invention is to provide improved construction in the switch mechanism aside from the magnetic control referred to.

Another object of my invention is to provide an improvement in spring operated contact arms for switches of the type herein specied.

Another object of my invention is to provide a switch of the type specified utilizing a substantial amount of insulating material in its construction thereby effectively avoiding short circuits.

Other, further and incidental objects of the invention will be seen upon reading the description following, aided by the drawing, wherein- Figure 1 is a side elevation of my improved switch.

Figure 2 is a plan view of my improved switch.

In the drawing, the embodiment of my inven- 45 tion shown is primarily directed to a thermostat controlled switch operating in a temperature control system, the particular embodiment iinding use in incubators, which will be seen to comprise a main base or support member I preferably formed of suitable insulative material in order to avoid short circuits as will be hereafter evident. Base I is somewhat elongated and has one end penetrated by an end of sleeve 2. The opposite end of the sleeve penetrates cross mem- 55 ber 3. The respective ends are held securely in base and cross member. Secured to each end of the cross member 3 is a thermostat wafer 4 which have centered pins 5 on the side opposite to which cross member 3 is secured. Secured to these pins is a second cross member 6, extending 5 from the pin of one wafer to the pin of the other. As is well known, adistortion occurs in thermostat wafers during periods of temperature change, and in this particular instance a rise of temperature causes cross members 3 and 6 to separate l0 and a lowering of temperature causes them to approach each other; however, in view of the fact that cross bar 3 is held stationary, bar 6 moves toward or from it as the case may be.

Secured to cross member 6 and extending conl5 centrically with sleeve 2 and member I is a link or rod l, one end being secured to cross member 6 and the other being threaded to receive nut 8. Rod 1 penetrates a rocking or switch arm 9, there being suicient play between members I and 9 to 2o avoid a rigid connection. Arm 9 is carried on a spindle or pin I0 which has its ends seated in spaced brackets II, the latter being secured by screws I 2 to the base I. Secured to rocking arm 9 is a U-shape spring arm I3. The spring arm has 25 one leg thereof secured to arm 9 by means of the screw I 4 and the threaded member I5 and the nuts I6 threaded thereto, the member I5 serving as a support for the weight II which is threaded thereto. The other leg terminates in a contact 3c member I8. Spaced from member I8 and likewise secured to the spring arm is a keeper or bar I9 serving a purpose hereafter described. In proximity to the contact I8 and secured to base I by means of screws 20 is a contact support 35 member 2I carrying contact 22 which is engaged by contact I8.

As will be understood, weight I'I urges spring arm toward base I causing engagement of contacts I3 and 22. The wafers 4 under proper tem- 40 perature conditions operate through the medium of line 1 to move arm I3 from the base as is well known, the nut 8 being suitably adjusted for this purpose, thus disengaging contacts I8 and 22. In the embodiment illustrated, the switch is closed upon a lowering of temperature, and opened upon a rise of temperature, though it is to be understood that a rearrangement of the parts may be had without departing from the invention whereby an opposite operation is obtained, to-wit, a rise in temperature closing the switch and a lowering of temperature opening the switch, thus making the apparatus particularly desirable for air cooling and circulation systems. In order to complete a circuit through the switch one wire thereof is attached to the moving arm I3 or to one of the brackets II as by means of one of the screws I2 and the other wire is secured to support 2| by any suitable means such as a screw 2|, the respective connections being shown by wires 23 and 24.

In switches of this type it is desirable that their opening and closing be hastened in order to avoid arcing and to reduce burning of the contacts. Magnets have been used for this purpose in connection with movable spring arms, the spring arm carrying the moving contact. The magnet in this instance resists the opening of the contact causing the arm to spring to a degree that the unspringing urge thereof overcomes the magnetic pull and the switch snaps open so quickly that arcing and burning of contact is substantially eliminated. In closing, the magnet, after the arm has moved close thereto, rapidly closes the contacts by springing the arm. In magnetic controlled switches of this type there is during the interval of their use a reduction in the size of the contact members seriously alterating the operation of the magnet unless compensated for, in other words the poles of the magnet have tobe moved in accordance with the wearing away of the contacts. This I provide for as follows:

A fulcruming or tilting means is provided on base I and this may be in the nature of a pair of rounded members 25A On these a magnet supporting bed 26 which is here shown as being an elongated rectangular member rests. At opposite ends of the member 26 are screws 21 and 28 respectively. These screws thread into base I. On bed 26 is secured a permanent horseshoe magnet 29 by means of screws 30 or other means suitable for the purpose. The poles 3l of magnet 29 are positioned in proximity to the contacts I8 and 22 and the keeper I9. Magnet attracts keeper or bar I9 thereby utilizing the spring action of arm I3 to hasten opening and closing of the contacts I3 and 22 as heretofore explained. The poles 3! of the magnet may be moved or tilted toward base I and away from bar I9 in accordance with the wear of the contacts I8 and 22 by unthreading screws 21 and. threading screws 28 a suitable amount. When this is done, the bed 26 which is resting upon fulcrums 25 has the end thereof supporting the magnet poles moved or tilted toward base I, thus adjusting the poles to a desired position. From the foregoing it will be seen that at all times the magnet poles can be placed and maintained in a position to properly control the operation of opening and closing the switch regardless of the degree of wear occasioned in the contactsr I8 and 22.

While a specic embodiment of my improvement has been described and illustrated herein, it is desired to be understood that the same may be Varied, within the scope of the appended claims, without departing from the spirit of the invention.

Having described my invention, I claim- 1. In an adjustable support for a magnet employed to hasten the closing and retard the opening of electric switches, a bed for supporting such magnet, fulcruming members supporting the bed intermediate its opposite ends, and threaded members at the ends of the bed operable to tilt the bed upon the fulcruming members for the purpose of altering the position of the poles of the magnet.

2. In an adjustable support for a magnet employed to hasten the closing and retard the opening of electric switches, a bed for supporting such magnet, a pair of rounded members supporting the bed intermediate its ends, and members at the ends of the bed operable to tip the bed upon the rounded members for the purpose of altering the position of the poles of the magnet.

3. In an adjustable support for a magnet employed to hasten the closing and retard the opening of an electric switch, a supporting member for the magnet, a rigid support carrying the supporting member intermediate its ends, and screw members at each end of the supporting member operable to tip the supporting member upon the rigid support for the purpose of altering the position of the poles of the magnet.

DAVID M. HOLBROOK. 

